Precision cross-winding apparatus



R. JENNY Oct. 10, 1967 PRECISION CROSS-WINDING APPARATUS 3 Sheets-Sheet 1 Filed July 19, I965 Oct. 10, 1967 R. JENNY PRECISION CROSS-WINDING APPARATUS 5 Sheets-Sheet 2 Filed July 19.. 1965 INVENTOR Tnulj wmw-U Oct. 10, 1967 Filed July 19, 1965 R. JENNY PRECISION CROSS-WINDING APPARATUS 3 Sheets-Sheet INVENTOR United States Patent Ofifice 3,346,207 Patented Oct. 10, 1967 3,346,207 PRECISION CROSS-WINDING APPARATUS Rudolf Jenny, Thaiwil, Switzerland, assignor to Maschinenfabrik Schweiter AG., Horgen, Switzerland, a corporation of Switzerland Filed July 19, 1965, Ser. No. 472,906 Claims priority, application Switzerland, July 21, 1964, 9,524/64; July 9, 1965, 9,687/ 65 Claims. (Cl. 242-45) ABSTRACT OF THE DISCLOSURE A precision cross-winding apparatus which incorporates at least one winding station for winding yarn into a package, a yarn delivery device for feeding yarn to the winding station, and an infinitely variable drive including speed adjustment means provided for the aforesaid Winding station to efiect winding of the delivered yarn into said yarn package. Additionally, a further infinitely variable drive including speed adjustment means is operatively connected with the infinitely variable drive for the yarn package and coacts with the yarn delivery device, and means are provided for forceably conjointly actuating in a predetermined relationship said adjustment means of both of the aforesaid infinitely variable drives.

The present invention has reference to an improved precision cross-winding apparatus, primarily for processing elastic or stretchable windable material, for instance crimp yarn and elastic yarn, e.g. rubber-like yarns, for cross-winding the same with uniform, controlled yarn tension and eliminating tension fluctuations emanating from the wind-olf body.

The problem of processing elastic or stretchable yarn Without fluctuations in tension to the maximum degree possible, in other words to deliver to the yarn tensioning device or brake mechanism a yarn which is as free as possible from tension has attempted to be solved in that, for example dyed strands are reeled onto cross-winding machines, former type winding machines, or winding frames, in order by winding twice to compensate to a certain extent prevailing differences in tension. On the other hand, at precision cross-winding machines or crosswinders, yarn delivery devices have been installed at which the yarn is supplied to the take-up spool or yarn package via one or two parallelly connected smooth cylinders or drums driven with constant rotational speed while utilizing a certain slip of the yarn at the drums. In so doing, the speed of rotation of the spindle of the cross-wound yarn package is reduced with increasing diameter of the yarn package or cheese wound thereon in order to obtain a yarn speed which is as constant as possible. Due to differences in the characteristics of the generally employed rotational speed varying means and the increase of the peripheral speed during build-up of the cheese or cross-wound yarn package at the bobbin sleeve there, however, results a more or less arched and increasing yarn speed curve. As a result, the yarn delivery device for the cross-wound yarn package in the terminal phase delivers too little yarn in comparison with the starting phase. This can lead to the formation of new yarn tension and, thus, to improper cross-wound yarn packages or cheeses possessing poor pay-01f properties. Moreover, the condition that the take-11p bobbin spindle and the yarn delivery device are not synchronously coupled with one another, particularly during starting and slowing-down of the winding station, acts as a disturbance source. A further condition which negatively influences the winding operation is that, with known constructions the rotational speed variators are directly actuated by an element which tests or scans the diameter of the yarn package, for instance a pressure or support roller. This results in that an increased and non-uniform pressure is exerted upon the aforementioned feeler element and can again lead to improperly wound yarn packages possessing poor payoff characteristics.

Accordingly, it is a primary object of the present invention to provide an improved construction of precision cross-winding apparatus which eifectively overcomes the mentioned disadvantages.

A further considerable object of this invention is directed to an improved precision cross-winding apparatus which winds yarns or other filamentous materials in such a manner that the Wound yarn is as free as possible of tension fluctuations, possessing a relatively uniform controlled yarn tension.

Still a further important object of this invention is to provide an improved construction of precision cross- Winding apparatus for winding up yarns or the like such that they possess good pay-ofi characteristics.

Another object of the present invention is directed to an improved precision cross-winder which effectively controls yarn tension at the individual winding stations, even when restarting winding at a station where there already exists a partially wound yarn package.

The precision cross-winding apparatus designed according to the teachings of the present invention embodies a yarn delivery device, an infinitely variable bobbin spindle drive, means for testing the diameter of the crosswound yarn package and which cooperates with the bob bin spindle drive in order to influence the speed of r0ta tion of the spindle as a function of the increase of the diameter of the yarn package. Characteristic of the invention is that a further infinitely variable drive which is operatively connected with the yarn delivery device is connected with the drive of the infinitely variable bobbin spindle drive, and that adjusting elements are provided for both infinitely variable drives which are forcibly conjointly capable of actuation in a certain predetermined proportionality or relationship via a drive.

Preferably, the cylinders or drums of the yarn delivery device are continuously positively connected with the wind-up bobbin spindle while providing for a constant proportionality of the peripheral speed of the cross-wound yarn package which is changeable in diameter to that of the aforesaid drums of the yarn delivery device. In so doing, the constant proportionality or relationship can be relatively changed in accordance with the coefficient of friction, the elasticity or stretchability of the windable material and/ or the desired slip, and the peripheral speed can be maintained constant, or for economic reasons slightly increases during the entire winding operation, and specifically is free of delay and without influencing the quality of the wound yarn packages by the yarn packagediameter feeler and adjusting elements. Consequently, there is ensured for the winding of yarn packages or cheeses possessing uniform tension which is controllable.

Other features, objects and advantages of the invention will become apparent by reference to the following detailed description and drawings wherein like reference characters have been used for substantially the same or analogous elements throughout the various embodiments, and in which:

FIGURE 1 schematically illustrates the general physical structure of a preferred embodiment of inventive precision cross-winding apparatus;

FIGURE 2 is a perspective view showing details of the drive and control for the winding apparatus depicted in FIGURE 1;

FIGURE 3 is a fragmentary, longitudinal sectional view showing a detail of the driving friction wheel or disk of the arrangement of FIGURE 2;

FIGURE 3 is a vertical sectional view of the arrangement of FIGURE 2, taken along the lines IVIV thereof;

FIGURE 5 schematically illustrates details of the mechanical control elements of the arrangement of FIG- URE 2;

FIGURE 6 is a view analogous to FIGURE 5, yet depicting the elements in a position corresponding to a different operating condition;

FIGURE 7 is an electrical circuit diagram for the embodiment of winding apparatus depicted in FIGURES 1 to 6;

FIGURE 8 is a graph depicting the resulting speeds of rotation for the operating conditions of the inventive .apparatusaccording to FIGURES 2, 5, 6 and 7;

FIGURE 9 is a graph depicting yarn tension before and after the yarn delivery device;

FIGURE 10 is a perspective view of a second embodiment of inventive precision cross-winding apparatus; and

FIGURE 1 1 is a circuit diagram for the embodiment of winder apparatus depicted in FIGURE 10.

Turning attention now to the drawings, it will be appreciated that in the schematically illustrated winder or winding apparatus of FIGURE 1, the yarn 2 or otherwise travels from a conventional reel 1 via a resiliently biased stop motion or cut-off arm 3 to a deflecting roller 4 or equivalent expedient, then back to the stop motion or cutoff arm 3 and, thereafter, passes from a conventional paraflining device 5 to a yarn delivery device 6. In the exemplary embodiment the yarn delivery device 6 is formed of a pair of cylinder rollers or drums 6a, 6b. Upon leaving the roller 6b this yarn 2 travels via a moistening apparatus 7 through a conventional brake or yarn tensioning device 8, over a stop motion or cut-off bracket 9, then over the to-and-fro moving yarn guide 19, between the pressure roller 11 and the cross-wound yarn package or cheese 12 carried by the bobbin spindle, generally indicated at reference 12a of FIGURE 4, and the sleeve 12!), to then become wound onto the surface of such yarn package 12. The yarn package 12 is rotatably mounted upon a bracket 13 neighboring the pressure or support roller 11. The bracket 13 in turn is pivotally mounted to a hub or sleeve 32.

The relatively long stop motion arm 3 which is pulled upwards by adjustable spring force and the multiple wrapping of the yarn 2 about such stop motion arm 3 and the roller 4 prevents stretching or rupture of the yarn 2 upon sudden interruption in the delivery of yarn due to possible pay-off disturbances at the reel 1. Due to the described arrangement a suflicient reserve of yarn is provided which is then payed-0E by pivoting the stop motion arm 3 through a certain angle in clockwise direction until the pay-off disturbance at the reel is automatically removed. Should this pay-off disturbance not be automatically removed, for instance on account of entanglement of the yarn 2 at the reel 1, then the stop motion arm 3 is pulley downwardly through the mentioned predetermined angle, and in this case, then, actuates a switch 14 (FIGURE 6), whereby a current circuit 15 is closed. An electromagnet 16 is located in this current circuit 15 which, upon excitation, brings to standstill the relevant winding station or location W in a manner to be described more fully hereinafter. Shutdown of the winding station W can also be achieved by the stop or cut-oif yarn feeler bracket 9 in that such can likewise close this current circuit 15 by means of a switch 17 if, due to yarn rupture or depletion of the yarn at the reel 1, the yarn tension after the yarn tension or brake device 8 disappears, and

the cut-01f feeler bracket 9 consequently falls forwards to thus actuate the switch 17.

' In FIGURE 2 there is illustrated in perspective view the details of an exemplaryembodiment of drive and control for a winding station W and it should be understood that in order to render the drawings more understandable the spatial position of some of the elements relative to one another has been shifted from the actual position they would occupy at the machine and also the elements are not shown exactly to scale. This, however, should not impair in any way a clear understanding of the inventive apparatus since the actual cooperation between the various components of the described system is fully explained. The course of travel of the yarn 2 is analogous to that described in conjunction with FIGURE 1 and should be kept in mind when considering the arrangement of FIGURE 2. Moreover, for the purpose of providing clarity in illustration, in FIGURE 2 all elements which are not concerned with the drive have not been illustrated, that is, only those components of the inventive apparatus necessary to understand the underying teachings of the invention have been depicted in FIGURE 2.

It will be understood that at a precision cross-Winding machine having a plurality of winding apparatuses adjacent one another a shaft 18 extends over the entire length of the machine and is driven by a non-illustrated electric motor. This shaft 18 serves as common drive shaft for all winding stations W. A respective friction wheel or disk 19 is arranged upon this drive shaft 18 in the region of each winding apparatus. Each of these friction wheels or disks 19 is connected for rotation through the agency of a relatively long hollow cylindrical hub 20 with the drive shaft 18, yet is displaceable in axial direction. As best seen by inspecting FIGURE 3, a helical spring 21 arranged in the annular compartment 20a between drive shaft 18 and hollow hub 20, bears at one end 21a at an entrainment pin 22 providing the rotational connection and at the other end 21b at the hollow hub 20 and friction disk 19 respectively. This spring 21 has the tendency to always press friction disk 19 against the largest diameter of a friction plate or wheel 23 cooperating with it. Friction plate 23 is rotatably connected via a key or wedge 24 with a shaft 25 and is axially displaceable upon such. Moreover, friction plate 23 is pressed by means of a spring 26 against the friction disk 19, so that both are positively coupled with one another by friction. A shift or control fork 27 engaging in an annular groove 28 at the hub 23a of the friction plate 23 is in operable connection via pull rod 29 with the previously considered electromagnet 16 (FIGURES 5 and 6), so that upon excitation of such electromagnet 16 the friction plate 23 is pulled away from the friction disk 19 against the action of the spring 26 (FIGURE 6), thereby interrupting the positive drive connection between these members.

Shaft 25 drives the wind-up or take-up yarn package 12 via a belt drive 30. The bracket 13 carrying the Windup yarn package 12 is pivotably mounted via the hub 32 and with respect to the housing 33 of the winding location about two axes. This bracket 13 is pressed via a spring 34 with adjustable force radially towards the pressure or support roller 11, whereas the spring 36 pivots this bracket 13 relative to the hub 32 such that the yarn package 12 during rotation always bears along a surface line at the pressure roller 11. The support for the pressure roller 11 and the guide means 37 for the yarn guide 10 are fixedly connected in non-illustrated manner with the housing 33.

A second friction disk or wheel 38 is positively coupled by friction with the friction plate 23 at the face or side of this friction plate 23 which is opposite the friction disk 19. This second friction disk 38 which is displaceably mount ed upon a shaft 39 is rotatably mounted at a cylindrical support 40 and drives via the shaft 39 and a belt drive 41 the transmission roller 42, the belt drive 43, and the shaft 44. The shafts 44 and 45 which carry the cylindrical rollers or drums 6a, 6b of the yarn delivery device 6 are rotatably connected with one another via a suitable belt or cord drive arrangement 46, are disposed in one plane, yet are at a certain angle with respect to one another so that the yarn 2 wrapped about both drums 6a, 6b of the yarn delivery device 6 follow a naturally ascending or increasing line i.e. screw line, and special yarn guides are not necessary, as would be the case for instance with yarn delivery devices having only one drum where the individual wrappings have to be separated from one another by means of a comb or the like.

Furthermore, a threaded spindle 48 is mounted beneath and parallel to the drive shaft 18. Spindle 48 carries a nut 47 which is parallelly guided by guide rail means 49. Nut 47 carries a pressure roller 51 at a support or holder 50 which is rigidly connected with it, and against which bears the friction plate 19 pressed by the spring 21 towards the largest diameter of friction plate 23. Due to appropriate rotation of the spindle 48 it is possible to displace the friction wheel or disk 19 towards the center of the friction plate 23, whereby the speed of rotation of the winding station drive shaft 25 increases in stepless or infinitely variable manner. If the spindle 48 is rotated in the opposite sense the friction disk 19, under the action of the spring 21, follows the pressure roller 51 and the rotational speed of this drive shaft 25 decreases in stepless manner.

A further threaded spindle 52 is arranged beneath and parallel to the shaft 39. This spindle 52 carries a nut member 54 which is parallelly guided by the guide rail means 53. A rocker arm 55 constructed at its upper end in the form of a sleeve 56 is articulated at 55a to the nut member 54. This rocker arm 55 is pressed towards the friction plate 23 by means of a blade or leaf spring 57 fixedly screwed or otherwise fastened onto the nut member 54. The cylindrical support 40 for the shaft 39 and the friction disk or Wheel 38 is seated for lengthwise displacement in the sleeve 56 and can be fixedly clamped by means of an adjustment or winged set screw 58. The arrangement of the friction disk 38 brings about that adjustment of the speed of rotation takes place forcibly in both directions by means of the spindle 52 and the nut 54, and that the frictional drive of the friction disk 38 with the friction plate 23 is continually maintained by means of the leaf spring 57. On the other hand, the frictional drive between the friction disk 19 and the friction plate 23 can be released by the control or stop motion arm 3 via switch 14 or by the stop bracket 9 via switch 17, since by means of any one or both of these switches 14, 17 the current circuit 15 is closed, the electromagnet 16 excited, and thus the control or pull rod 29 pulled into such electromagnet. Due to the operable connection of this control rod 29 via the shift fork 27 with the annular groove 28 the friction plate 23 is removed from the friction disk 19 against the action of the spring 26, and the entire winding station or location W brought to standstill, whereby, due to the continuous, positive connection within the winding location, the drums 6a, 6b of the yarn delivery device 6 follow each movement of the cross-wound yarn package 12.

With constant winding and yarn speed each diameter of the increasing yarn package 12 corresponds to a certaln position of the friction disk 1'9 driving the package winding spindle 12a and which is ensured for by control means to be described more fully later. From the requirement that the yarn speed or velocity is maintained constant or only increases slightly throughout the entire formation of the yarn package 12 it follows that the speed of rotation of the package spindle 12a must be reduced with increasing diameter of the yarn package 12. This is achieved by displacing the friction disk 19 at the friction plate 23 from the inside towards the outside.

In the graph of FIGURE 8 the yarn velocity or speed V is plotted as a function of the yarn package diameter D, the curve 59 representing the course of this yarn velocity. At the same time the requirements exists that there is maintained the proportionality or ratio of the peripheral speed of the drums 6a, 6b of the yarn delivery device 6 with respect to the yarn speed, and that the peripheral speed of these drums of the yarn delivery device 6 must be higher than the yarn speed by a certain amount throughout the entire formation of the yarn package, namely by the amount of the slip. This is achieved in that the friction disk 38 with reduction of the speed of rotation'of the revolving friction plate 23 is displaced from the inside towards the outside, whereby, re-supposing the same conditions or ratios for both speed of rotation variators, there results for the drums of the yarn delivery device 6 a constant speed of rotation and a constant peripheral speed, as such is depicted in FIGURE 8 by the horizontal lines 60; and according to FIGURE 2 is realized by rotational connection of both adjustment spindles 48 and 52 by means of the gears 61 and 62. FIGURE 8 clearly shows the resultant reduction of the dilference in slip. For such reason, the gear 61 of FIGURE 2 is selected to be larger than the gear 62, there results for the spindle 52 a higher speed of rotation, for the friction disk 38 a larger adjustment path and, consequently, for the drive of the yarn delivery device 6 an increased rotational speed. Such analagously corresponds to an increasing peripheral speed of the rollers or drums 6a, 6b of the yarn delivery device 6. Instead of using two gears 61 and 62 which are unequal in size, it is possible to employ two equally large gears. In this case, then, two adjusting spindles 48 and 52 with different thread pitch provide the desired compensation. Due to appropriate selection of the transmission ratio of the gears 61 and 62 it is possible to make the curve of the peripheral speed of the drums 6a, 6b of the yarn delivery device 6 practically parallel to the yarn speed 59, as such has been represented in FIGURE 8 by the curve 63.

In order to be able to take into account the different properties of the material of a yarn, such as coefficient of friction, elasticity, elongation and so forth, the slip, re. the speed difference between the yarn speed and the peripheral speed of the drums of the yarn delivery device, can be optionally adjusted in that the basic position of both friction disks 19 and 38 can be changed relative to one another, specifically by displacing the cylindrrcal support 40 in the sleeve 56 (FIGURES 2 and 5). In so doing, such displacement towards the center of the friction disk or plate 23 corresponds to a reduction of the slip because without adjusting the first rotational speed varrator or varying means 19, 23 the starting speed of rotatron of the second rotational speed variator or 23, 38 rs reduced and the difference due to the rigid rotational connection of both adjustment spindles 48 and 52 via the gears 61 and 62 remains constant. An increase of the slip can be obtained in analogous manner by displacement of the cylindrical support 40 in a direction towards the largest diameter of the friction plate 23. This possibility of adustment is graphically depicted in FIGURE 8 by the curves or lines 63a and 63b which correspond to the respective positions of the friction disk 38 shown in phantom lines in FIGURES 5 and 6 respectively, and likewise designated by reference characters 63a and 63b respectively.

, The control of the first drive or rotational speed variator 19, 23 and the adjustment of its frictional wheel or disk 19 as a function of the increasing diameter of the yarn package 12 takes place by means of a servo-follower control device, illustrated by way of example in the circuit diagram of FIGURE 7. The main components of such control device embody a bridge circuit A, the switching or control emplifier B and the servomotor M, in addition to the-necessary switch elements. A potentiometer 64 possessing a tap 64a and providing a so-called reference value transmitter, is rotatably connected via a gear 65 and a gear segment 66 with the hub 32 for the cross-wound yarn package 12 (FIGURE 2) and, thus, is directly dependent in its set or adjusted position upon the diameter of the yarn package 12. A second potentiometer 67 having a tap 67a and providing a so-called actual value transmitter, is rotatably connected with the elongated adjustment spindle 48 by means of the worm gear 68 and worm 69 supported at the aforesaid elongated adjustment spindle 48. Thus, the second potentiometer 67 has its setting made directly dependent upon the position of the nut 47, the control roller 51, and the friction disk 19. Both of the potentiometers 64 and 67 provide in the bridge circuit A,

the mode of operation of which is well known to the art, transmitters which must be correlated to one another, whereby the transmitter 64 (FIGURE 7) is positively controlled and the second transmitter 67 follower controlled in that, depending upon the setting of the transmitter 67 with respect to the position of the transmitter 64 the conrol element e.g. relay 70 or 71 is actuated by the control amplifier B.

In FIGURE 7 both of these control or switch elements 70 and 71 are shown in their rest positions. The electric motor M is coupled in a current circuit 72. Such motor M is provided with a contact 73 for rotation in counterclockwise direction and a contact 74 for rotation in clockwise direction. Just as the worm 69 is seated upon the elongated adjustment spindle 48 also is this motor M and it is rigidly connected for rotation with such spindle 48. If, now, the transmitter 64 advances due to an increase of the diameter of the yarn package 12 then the control or switch element 71 responds and actuates the doublethrow switch 75, i.e. contact 73 is open and contact 74 closed. Consequently, the current circuit 72, 74, 77 is closed and the electric motor M rotates in clockwise direction. With this rotation the position of the transmitter 67 is also forcibly changed in the sense that it lags or trails behind the transmitter 64 until it has reached the latters setting and, thus, the double-throw switch 75 returns back into its rest position by means of the switch element 71, the current circuit 72, 74, 77 being opened and the motor M shut-off. If, for any reason, the transmitter 67 leads the transmitter 64, then the control or switch element 70 responds and via the double-throw switch 77a closes the contact 76. Now, the current circuit 72-76-73 is closed and the electric motor M rotates in counterclockwise direction until there is reached a position of balance for both transmitters 64 and 67, the switch 77a returns back into its rest position, the motor M again coming to standstill.

Instead of using the previously described servo-follower control device one of a diiferent physical type could be provided, such as mechanical-electrical, whereby two condition-dependent points serving as transmitter means can be articulated with one another by a rod, to both sides of the center of which a respective switch-in switch and switch-out switch are mounted in operable cooperation with this rod and in such a manner that when pressure is exerted upon such switches the corresponding current circuit is closed. If, now, the one transmitter point is in adjustment-connection with a servomotor M and if the other is adjusted to positively lead or trail, then in analogous manner the switch disposed before or after the rod responds, whereby such controls the motor for running tothe right or left and the secondary transmitter point is permitted to follow the primary until reaching the balance position.

The described exemplary embodiment of precision cross- Winding apparatus, particularly its drive, due to connecting in series two rotational speed variators whose adjustment mechanism are positively or forcibly coupled in a certain ratio and dependency upon one another and wherein the relative base adjustment of the rotational speed variators can be changed with respect to one another for the purpose of accommodating the slip to the particular properties of the material being processed, i.e. accommodation of the difference of the yarn speed onto the yarn package to the peripheral speed of the drums of the yarn delivery device, renders it possible to process into Wound yarn packages of high quality the most different windable materials. In other words, it is possible to form wound yarn packages with uniform, lower yarn tension in accordance with the purposes to which the yarn is to be put, in that, the yarn delivery device compensates pronounced tension fluctuations generated by reeling-01f and delivers such yarn to the brake device 8 practically free of tension, as such is graphically depicted in FIGURE 9. In this figure, there is plotted along the ordinate yarn tension in grams (g.) and the yarn tension curve before the yarn delivery device 6 is designated by reference character 78 and after such by reference character 79. The correspond ing locations have been designated in FIGURE 1 also by reference numerals 78 and 79.

The second embodiment of cross-winding apparatus according to FIGURES 10 and 11 considerably corresponds to the previously described first embodiment already considered in detail. Insofar as the components of the embodiment of FIGURES l0 and 11 correspond to those of the first embodiment the same reference characters have again been employed for like or analogous elements. In FIGURE 10, reference character W generally designates the winding station or apparatus and reference character 6 the yarn delivery device. Instead of the gears 61 and 62 which couple the adjustment spindles 48 and 52 with one another, here the threaded spindle 48 carries a friction wheel or disk 102 and the adjustment spindle 52 a friction disk or wheel 103. In so doing, a friction wheel 104, the shaft of which is substantially perpendicular to the spindles 48 and 52, couples both friction disks 102, 103 with one another. The shaft 105 is mounted in a support 106 which is displaceably guided in any suitable known manner in axial direction and, for instance, can be displaced by means of a non-illustrated, conventional hand wheel and an adjusting spindle. The elements 102, 103 and 104 thus form a further infinitely variable drive, by means of which the ratio of the setting or adjustment of both spindles 48 and 52 can be changed with respect to one another. At a scale 108 with which cooperates a pointer 107 connected to the support 106 it is possible to read-out the functional relationship of yarn package speed of rotation and yarn package diameter and the yarn speed.

Due to the regulation or adjustment of such relationship it is possible, among other things, to achieve an increase in efficiency. This situation can then occur if the yarn package speed at the beginning of the winding operation is not limited by the yarn speed i.e. with a still small yarn package diameter; rather is limited by the highest possible number of strokes of the yarn guide. In this case, reduction of the rotational speed of the yarn package can be held smaller than would correspond to the increasing diameter, so that an increase of the yarn velocity or speed during the winding operation to the highest permissible value is possible, which corresponds to an increase in ef-' ficiency.

By referring to FIGURE 10 it is further apparent that the rod 29 of the shutdown or stop motion device which removes the friction plate 23 from contact with the friction wheel or disk 19, is operably associated with a switch 109 which is actuated i.e. opened by the rod 29 when shutdown occurs. This switch 109 is arranged in the bridge circuit A of the follower control device, the circuit diagram of which is depicted in FIGURE 11. At that side of the circuit which corresponds to the tap-off location during winding of smaller yarn package diameters i.e. thus corresponds to larger rotational speeds, there is connected in front of the reference transmitter 64 and parallel to the switch 109 disposed in the branch circuit 111 a so-called disturbance resistance whose resistance value is comparatively quite large. This reference transmitter 64 is provided at the opposite side with a series connected potentiometer 112 which can be adjusted from a resistance value null up to a very high value in comparison with the resistance of the transmitter 64. The potentiometer 112 i provided in known manner with a scale.

Now, if the winding location or station W is brought to standstill because of, for instance, yarn rupture and by means of a yarn monitor for instance which in known manner switches a non-illustrated electromagnet which, in turn, pulls back the control rod 29 (FIGURE 10) and raises the planar friction disk 23 from the driving friction wheel 19, then the control rod 29 simultaneously actuates the switch 109. This switch 109 thus opens the shunt or branch circuit 111 (FIGURE 11) whereby the reference transmitter 64 is connected in series with the resistor 110. This very large increase of resistance at the side of the transmitter 64 corresponding to the smallest yarn package diameter is the same. as if the transmitter 64 i.e. its tap 64a were suddenly adjusted mechanically downwards, in other words, into a position corresponding to the largest yarn package diameter. As a result, the tap 67a of the transmitter 67 will trail behind the new setting thus obtained by the transmitter 64 into the setting of the lowest rotational speed.

Thereafter, if the winding location or station W is again swtched-in, the control rod 29 releases the cut-off or stop switch 109 and such again closes the shunt connection 111, whereby the series resistor 110 is switched-out or bridged. As a result, the conditions prevailing .at the tr nsmitter 64 directly prior to standstill of the relevant Winding-location W are again brought about, whereby the transmitter 67 is caused to hurry behind the transmitter 64 until it reaches the setting which the transmitter 67 had directly prior to bringing the winding location to standstill. Thus, during each starting into operation of a winding location, after an interruption of the winding procedure, the winding operation begins with the smallest yarn package or bobbin spindle-rotational speed and with the smallest yarn speed, in order thereafter to be uniformly accelerated until reaching the value possessed directly prior to interruption of winding. The potentiometer 112 coupled with the transmitter 64 (corresponding to the position of the largest diameter of the cross-wound yarn package 12) renders it possible to adjustably increase the resistance of the positively controlled branch of the measuring bridge A. Due to the direct dependency of the transmitter 64 upon the diameter of the wound yarn package 12 the coupled-in resistance of the potentiometer 112 is mechanically not taken into consideration. Electrically, on the other hand, the entire or total resistance (resistance of transmitter 64 and the coupled-in resistance of the potentiometer 1 12) confronts the unchanged resistnce of the trailing transmitter 67.

In accordance with the mode of operation of the measuring bridge A, balance or equilibrium of the transmitter 64, 67 is provided if in both transmitters 64 and 67 the same conditions exist between the partial resistances before and after the tap. From this follows that in the transmitter 67 the portion of the resistance active for the follower control must be limited by an amount proportional to the resistance 112 coupled-in with the trans mitter 64, i.e. there is limited the control range of the yarn package rotational speed necessary for a constant peripheral speed during increasing yarn package diameter, so that the peripheral speed increases with increasing yarn package diameter. This increase of the peripheral speed of the yarn package 12 is accommodated to the peripheral speed of the rollers or drums 6a, 6b of the yarn delivery device 6 in that, the transmission ratio of the infinitely variable drive 102, 104, 103 between the adjustment spindles 48 and 52 (FIGURE 10) is changed by displacing the friction disk 104 between both of the planar friction disks 102 and 103. The relationship of the peripheral speed of the drums 6a, 6b of the delivery device 6 to that of the increasing yarn package 12 throughout the entire diameter range is also then maintained if the yarn speed is continuously increased by coupling a resistance 112 with the transmitter 64. Adjustment or setting of the friction disk 104 takes place in accordance with the scale 108, the division and markings of which are preferably in a logical relation to the scale of the potentiometer 112. It will be appreciated that both of the elements which are to be adjusted can also be coupled with one another by suitable non-illustrated mechanical elements or other suitable elements.

The described automatically occurring regulation before and after the shutdown or stopping of the winding location is particularly then of considerable importance if the thread or yarn isnot axally pulled-off but rolled-0E spools or strands which exhibit a considerable weight and corresponding inertia. The masses of the spools or strands which have to be accelerated would once again lead to yarn rupture upon sudden starting at normal rotational speeds. Previously, this condition was taken into account in that the winding stations were slowly and carefully switched-in manually in order to achieve slow starting by means of a certain slip. Hence, the described solution provides the advantage that this burden is removed from the operating personnel, resulting in a saving-in-time, and the switching-in of the winding locationsis made independent of the feel of the operating personnel.

While there is shown and described present preferred embodiments of the invention it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practised within the scope of the following claims.

What is claimed is:

1. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, comprising at least one winding station for winding yarn into a yarn package, a yarn delivery device for feeding yarn to said winding station, an infinitely variable drive including adjustment mean-s provided for said winding station to effect winding of the delivered yarn into said yarn package, means for checking the diameter of the yarn package cooperating with said infinitely variable drive for influencing the rotational speed of said yarn package as a function of the increase of its diameter, a further infinitely variable drive including adjustment means operatively connected with said infinitely variable drive for said yarn package and coacting with said yarn delivery device, and means for forcibly conjointly actuating in a predetermined relationship said adjustment means of both of said infinitely variable drives.

2. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 wherein said actuating means for both said adjustment means comprises a pair of cooperating gear members possessing a predetermined transmission ratio.

3. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 wherein said actuating means for both said adjustment means comprises another infinitely variable drive which enables said predetermined relationship to be selectively altered.

4. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 further including control means responsive to operation of said yarn package diameter checking means for controlling both said adjustment means of both said infinitely variable drives via said actuating means.

5. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 4, said control means including a servomotor for operatmg both of said adjustment means via said actuating means, a follower control mechanism for influencing operation of said servomotor, said follower control mechamsm including an actual value transmitter operably coupled with said adjustment mechanisms of both said infinitely variable drives and a reference value transmitter operably coupled with the yarn package.

6. Precision cross-winding apparatus, particularly for Wllldll'lg stretchable and elastic yarns, as defined in claim 5, said reference value transmitter including a gear, said yarn package diameter checking means incorporating a prvotably mounted support for carrying th yarn kage and a gear element meshing with said gear of said reference value transmitter.

7. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 5 wherein each of said adjustment means for both infinitely variable drives incorporates a threaded spindle and a nut member displaceably carried by said thread d 1 1 spindle, said actuating means for both said adjustment means including a transmission gear unit for driving interconnection of said threaded spindles, one of said threaded spindles being coupled with said servomotor.

8. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 wherein both of said infinitely variable drives incorporate friction disk means, one of said friction disk means providing a driven disk for said infinitely variable drive for said yarn package and at the same time a driving disk for said further infinitely variable drive for said yarn delivery device.

9. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 8 wherein said further infinitely variable drive incorporates a friction disk member driven by said driven disk provided by said one friction disk means, and means mounting said friction disk member and said one friction disk means so as to be conjointly displaceable in order to bring to standstill the associated winding station.

10. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 wherein said yarn delivery device incorporates a pair of drum members disposed substantially in a common plane and the lengthwise axes of which enclose an acute angle.

11. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 1 further including control means responsive to operation of said yarn package diameter checking means for controlling both said adjustment means of both said infinitely variable drives via said actuating means, said control means incorporating a servomotor for operating both of said adjustment means via said actuating means, a shutdown mechanism for interrupting the yarn winding operation at said winding station, said shutdown mechanism exhibiting a switch which when in open condition actuates said servomotor such as to reduce the speed of rotation of said infinitely variable drives.

12. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 11, and control means further including a follower control mechanism possessing a control circuit, said switch being coupled in said control circuit.

13. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 12, said control circuit including a bridge connection, a reference value transmitter coupled in said bridge connection, a disturbance resistance capable of being connected in series with said reference value transmitter via said switch.

14. Precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, as defined in claim 11, said actuating means including another infinitely variable drive for forcibly conjointly actuating both of said adjustment means of said infinitely variable drives and for selectively altering said predetermined relationship.

15. In a precision cross-winding apparatus, particularly for winding stretchable and elastic yarns, comprising at least one Winding station for winding yarn into a yarn pack-age, a yarn delivery device for feeding yarn to said winding station, an infinitely variable drive including speed adjustment means provided for said winding station to efiect winding of the delivered yarn into said yarn package, a further infinitely variable drive including speed adjustment means operatively connected with said infinitely variable drive for said yarn package and coacting with said yarn delivery device, and means for forcibly conjointly actuating in a predetermined relationship said adjustment means of both of said infinitely variable drives.

References Cited UNITED STATES PATENTS 1,952,782 3/1934 Steadley 242 FRANK J. COHEN, Primary Examiner.

N. L. MINTZ, Assistant Examiner. 

1. PRECISION CROSS-WINDING APPARATUS, PARTICULARLY FOR WINDING STRETCHABLE AND ELASTIC YARNS, COMPRISING AT LEAST ONE WINDING STATION FOR WINDING YARN INTO A YARN PACKAGE, A YARN DELIVERY DEVICE FOR FEEDING YARN TO SAID WINDING STATION, AN INFINETLY VARIABLE DRIVE INCLUDING ADJUSTMENT MEANS PROVIDED FOR SAID WINDING STATION TO EFFECT WINDING OF THE DELIVERED YARN INTO SAID YARN PACKAGE, MEANS FOR CHECKING THE DIAMETER OF THE YARN PACKAGE COOPERATING WITH SAID INFINITELY VARIABLE DRIVE FOR INFLUENCING THE ROTATIONAL SPEED OF SAID YARN PACKAGE AS A FUNCTION OF THE INCREASE OF ITS DIAMETER, A FURTHER INFINITELY VARIABLE DRIVE INCLUDING ADJUSTMENT MEANS OPERATIVELY CONNECTED WITH SAID INFINITELY VARIABLE DRIVE FOR SAID YARN PACKAGE AND COACTING WITH SAID YARN DELIVERY DEVICE, AND MEANS FOR FORCIBLY CONJOINTLY ACTUATING IN A PREDETERMINED RELATIONSHIP SAID ADJUSTMENT MEANS OF BOTH OF SAID INFINITELY VARIABLE DRIVES. 